Star-Crossed Telescope

THE STORY BEHIND FIXING HUBBLE'S VISION

by Todd Neff

Starting in the late 1970s, the Hubble Space Telescope became a Ball focus. The company’s 20-year relationship with NASA Goddard, which managed the Hubble program, paved the way. Ball engineers came to understand the space telescope as few did, and their Goddard High Resolution Spectrograph launched with Hubble in 1990. The company added instruments on subsequent shuttle-servicing missions, the most famous being COSTAR, the “eyeglasses” that helped fix Hubble’s hazy vision.

MURK BOTTEMA, Ball’s top optical engineer, designed COSTAR. Bottema was born in Velsen, the Netherlands, in 1923. As a young man during the waning days of World War II, he stayed off the Nazi-occupied streets during daylight hours for fear of being picked up and conscripted. He spent his time studying mathematics and physics and tinkering, at one point building a functioning clock with his Erector Set.Murk Bottema, the brilliant Ball optical engineer who was instrumental in fixing Hubble’s hazy vision.

Bottema was an Old World gentleman before, technically, he was a man. When his family moved to the Dutch town of Assen, a girl of 15 looked out her window to see a boy step out of the back seat of the family car and open the door for his mother. “The way he looked, so intelligent and so polite, I said ‘This is the man I’m going to marry,’” Willie Bottema recalled. And she did.

Her young husband went on to study physics under Nobel Prize winner Frits Zernike at the University of Groningen, where Bottema earned his PhD. During a year at Johns Hopkins University in 1958, he so impressed his hosts they asked him to return permanently. He emigrated with his wife and three young boys to work designing rocket-borne telescopes and spectrometers for the study of planetary atmospheres.

In 1968, Bottema joined Ball in Boulder. He was a quiet, serious man, with great confidence. As his wife put it, “He trusted his own brain.”

When the plan for the Hubble Space Telescope solidified in the 1970s, Bottema worked with NASA scientists on the design and came to know Hubble intimately. He proposed several Ball instruments for the telescope, three of which Ball would build. He retired in 1990, thinking his contributions to the space telescope were behind him.
Hubble was a silver-sheathed cannon four stories tall and weighing more than 12 tons. Technical problems pushed back a planned 1983 launch; the space shuttle Challenger disaster in January 1986 delayed a liftoff slated for August of that year. When Hubble finally launched in April 1990, it was to be capable of discerning the period at the end of this sentence from a mile away. It would, NASA promised, bring home images with ten times the clarity of the best earthly telescopes.

“In a thunderous overture to a promised new era in astronomy, the space shuttle Discovery rocketed into orbit today with the $1.5 billion Hubble Space Telescope, which scientists believe will give them a commanding view of the universe as it was, is and will be,” a front-page New York Times story gushed.

The tenor would change. Two months later, NASA announced that Perkin-Elmer Corporation, the mirror contractor, had ground the giant telescope’s eight-foot primary mirror with slightly less curvature around its fringe than they should have.

Hubble’s flaw, caused by what’s known as a spherical aberration, stretched the tip of the telescope’s point of focus so much that there was no real focal point. The mirror’s error was fantastically minor—roughly 1/25 of a hairsbreadth. Scaled up, the flaw would represent a difference less than the tip of a ballpoint pen across a football stadium. But with optics as precise as Hubble’s, the imperfect mirror affected not only image sharpness, but also the telescope’s ability to detect faint objects, which was to be one of Hubble’s greatest strengths.

Ed Weiler had spent a decade of his life on the most expensive science experiment in history, and NASA’s chief scientist for the space telescope understood it to be fundamentally flawed. He faced the press on June 27, 1990. “It would be dishonest to say the mood of the scientists is happy,” he said. “We’re all frustrated, obviously. But we should be able to fix it in the long run. Nobody’s walking away.”

The public reaction was swift and brutal. “Pix Nixed as Hubble Sees Double,”“Space Telescope Can’t See Straight,”“Hubble, Double, Toil and Trouble,” shouted the headlines. Newsweek put Hubble on its cover with the words: “Star Crossed: NASA’s $1.5 billion blunder.” U.S. Senator Barbara Mikulski of Maryland, a reliable space booster whose state hosted much of the NASA’s Hubble effort, called the telescope a “techno-turkey.” David Letterman piled on, the late-night comedian’s top-ten list of NASA excuses for Hubble including “The guy at Sears promised it would work fine,” and “Bum with squeegee smeared lens at red light.”

This cartoon in the Milwaukee Journal was one of many about Hubble’s mirror problems

Yet, scientists and engineers realized, Hubble had the advantage of having been ground to perfect imperfection. Even before Weiler spoke publicly of Hubble’s myopia, scientists suggested that future Hubble instruments be equipped with small mirrors intentionally shaped to cancel out the problem. As one Hubble scientist put it, “as applied to light waves anyway, two wrongs can make a right.” Jet Propulsion Laboratory engineers were already working on a second-generation replacement for Hubble’s main camera called the Wide field and Planetary Camera 2. They figured they could add a nickel-sized correcting mirror.

That was fine for a future instrument, but Hubble was flying now, with hundreds of millions of dollars in science projects drinking in bad light. NASA asked some of the nation’s top optical minds for ideas to salvage what was already in orbit. The Space Telescope Science Institute leading the Hubble astronomical effort formed the HST Strategy Panel, including famed astronomer Lyman Spitzer, astronaut Bruce McCandless and more than a dozen others. Bottema was among them.
Stay tuned for Part 2 of the Star-Crossed Telescope in the next Features edition.